The present invention relates generally to automated stacking of relatively thin porous and non-porous material layers and, more particularly, to apparatuses and methods for automatically stacking porous and non-porous layers of a fuel cell during fuel cell assembly.
Various apparatuses have been developed to stack layers of varying materials when constructing a stack of such material layers. Conventional stacking apparatuses typically employ suction cups or a vacuum to releasably engage and transport layers of a given material during a stacking operation. Although such conventional arrangements may be satisfactory in certain applications, implementing known approaches for stacking relatively thin materials having varying porosity renders conventional arrangements unworkable.
Moreover, it is often desirable to automate, either partially or completely, a number of processes of a stacking operation. Many conventional material handling, transporting, and stacking apparatuses and methods are not well suited for a high degree of automation, particularly stacking processes which have tight positional tolerance requirements.
There is a need for improved material layer stacking apparatuses and methodologies. There is a further need for such apparatuses and methodologies that can safely and precisely position and stack material layers of varying porosity in an automated assembly environment, such as in an automated fuel cell assembly plant. The present invention fulfills these and other needs.
The present invention is directed to methods and apparatuses for facilitating automated stacking of various material layers having varying porosity. In accordance with the present invention, the material layers subject to automated stacking typically include at least one substantially non-porous material layer and at least one substantially porous material layer. A method of stacking such material layers according to an embodiment of the present invention involves applying vacuum to a first porous material layer to stabilize the first porous material layer relative to a support structure. One or both of the support structure and a non-porous material layer are moved to establish contact between the non-porous material layer and the first porous material layer. The first porous material layer and the non-porous material layer define a sub-assembly. While applying vacuum to the sub-assembly, one or both of the support structure and a second material layer are moved to establish contact between the second material layer and the non-porous material layer. Vacuum applied to the sub-assembly maintains positional stability of the first porous material layer and non-porous material layer relative to the support structure while the second material layer is moved into contact with the non-porous material layer. Vacuum is subsequently removed to facilitate transporting of the material layer stack.
In accordance with one embodiment directed to automated fuel cell assembly, a number of fuel cell layers of varying porosity are processed, including at least a first fluid transport layer (first FTL), a second fluid transport layer (second FTL), and a membrane. The first and second FTLs are substantially porous and the membrane is substantially non-porous. The automated stacking process involves applying vacuum to the first FTL to stabilize the first FTL relative to a support structure. One or both of the support structure and the membrane are moved to establish contact between the membrane and the first FTL, the first FTL and the membrane defining a sub-assembly. While applying vacuum to the sub-assembly, one or both of the support structure and the second FTL are moved to establish contact between the second FTL and the membrane. The application of vacuum to the sub-assembly maintains positional stability of the first FTL and membrane relative to the support structure while the second FTL is moved into contact with the membrane. Vacuum is subsequently removed to facilitate transport of the fuel cell stack for downstream processing.
According to another embodiment, automated stacking of fuel cell layers is facilitated with use of a transportable fixture assembly comprising a first fixture and a second fixture. The first and second fixtures include at least one substantially porous region, respectively. The automated stacking process involves moving one or both of a first FTL and the first fixture to establish contact between the first FTL and the first fixture. One or both of the first fixture and a membrane are moved to establish contact between the membrane and the first FTL. The first FTL in contact with the first fixture and the membrane defines a first sub-assembly. One or both of the second fixture and a second FTL are moved to establish contact between the second fixture and the second FTL. The second FTL in contact with the second fixture defines a second sub-assembly. While respectively applying vacuum to the first and second fixtures, one or both of the first and second fixtures are moved to establish contact between the second FTL and the membrane. The application of vacuum to the first sub-assembly maintains positional stability of the first FTL and membrane relative to the first fixture, and the application of vacuum to the second sub-assembly maintains positional stability of the second FTL relative to the second fixture. Vacuum is subsequently removed from the first sub-assembly and the second sub-assembly to allow for the transport of the fuel cell stack for downstream processing.
In accordance with yet another embodiment of the present invention, an automated process of stacking and bonding fuel cell layers involves moving a second surface of a first FTL into contact with a first support of a bonding press. Vacuum is applied to the second surface of the first FTL to stabilize the first FTL on the first support. The membrane is moved into contact with a first surface of the first FTL, the first FTL and the membrane defining a first sub-assembly. Vacuum is applied to the first sub-assembly to maintain positional stability of the first FTL and membrane relative to the first support. Vacuum is applied to a first surface of the second FTL to stabilize the second FTL on a second support of the bonding press. One or both of the first and second supports are moved to establish contact between a first surface of the membrane and a second surface of the second FTL. The first FTL, membrane, and second FTL are bonded together to produce a bonded fuel cell assembly. The automated stacking and bonding processes may be employed to stack and bond material layers of varying types and porosity.
The above summary of the present invention is not intended to describe each embodiment or every implementation of the present invention. Advantages and attainments, together with a more complete understanding of the invention, will become apparent and appreciated by referring to the following detailed description and claims taken in conjunction with the accompanying drawings.